1. Field of the Invention
The invention relates to a process for regulating the fuel-oxygen ratio of exhaust gas in an exhaust gas duct upstream of a catalytic converter, wherein a secondary air pump injects secondary air into the exhaust gas duct upstream of the catalytic converter.
2. Description of the Related Art
A method for regulating the fuel-oxygen ratio of exhaust gas upstream of a catalytic converter of an internal combustion engine has become known from German published, non-prosecuted patent application DE 41 41 946 A1. In that method, air is injected into the exhaust gas duct upstream of the catalytic converter with a secondary air pump. The quantity of air pumped by the secondary air pump is adapted to the quantity of exhaust gas. To that end, the secondary air pump is either pilot-controlled, taking into account the load and rpm of the engine, or regulated, given an operationally ready lambda control. The control and regulation of the secondary air mass is relatively sluggish, and so a desired exhaust gas ratio can be established only relatively imprecisely.